312 Mr. J. Alder on some New and Rare Zoophytes” 
between these are eight others, almost tubercular. The peduncle 
is rather long and columnar, with four tufts of thread-cells sur- 
rounding the mouth. 
A single specimen only of this imteresting little Hydractinia 
was obtained, parasitical on a dead shell of Natica Alder, brought 
in by the fishing-boats at Cullercoats. I have since seen a dead 
and rather worn specimen, upon Natica Grenlandica, among the 
Zoophytes collected in Shetland by the Rev. A.M.Norman. The 
species differs from H. echinata in its much smaller size, the 
simple linear form of its spines, their irregular grouping, and 
more especially in its bearing medusoids ; these latter spring from 
the encrusting base. No capsule could be detected, but this 
might possibly arise from its great transparency. The medu- 
soids bear a great resemblance to those of Podocoryne carnea, 
Sars, the only difference being in their having eight inter- 
mediate tubercular tentacles. In this respect they also differ 
from the medusoid of a Hydroid polype described by Professor 
Lovén, and referred by him to Hydractinia, but which appears 
rather to belong to the genus Podocoryne, as the base was not 
horny or spinous. As far as I am aware, therefore, this is the 
only instance in which medusoids have been ascertained to be 
produced by a true Hydractima. 
Coryne implexa, Alder. 
Some confusion has arisen about this species, the polypary of 
which I described under the name of Tubularia implexa in my 
‘Catalogue of the Zoophytes of Northumberland and Durham,’ 
not having at that time been able to ascertain the character of 
the polypes, from which alone the genus in this group can be 
properly determined. Dr. T. Strethill Wright, however, has 
since met with it in a living state, and has found that it belongs 
to the genus Coryne. The Coryne figured in my ‘Catalogue’ 
under the provisional name of Coryne pelagica (pl. 7. fig. 2) ap- 
pears, in fact, to be the young of it. I have lately met with it 
again in this state at Cullercoats, and have ascertained that its 
medusoid is similar to the one described by Professor Allman as 
that of his C. Briareus, which I now think, with Dr. Wright, 
must also be referred to the same species. Specimens sent me 
from the Firth of Forth by the latter gentleman are intermediate 
in size between my Tubularia implexa and Coryne pelagica. The 
more humble growth appears to be not uncommon on our coast, 
as I have met with it several times on old crusted shells of Fusus 
antiquus, and Mr. G. Hodge has lately sent it me from Seaham 
Harbour, creeping over Cellepora pumicosa. As the curious and 
beautiful medusoid of this species has not yet been figured, I 
have given a representation of it in Pl. XIV. fig. 4. 
